1. Field of the Invention
The present invention relates to a radiographic image diagnosis apparatus suitable for Interventional Radiology as a low invasive treatment.
2. Description of the Related Art
Recently, in the medical field, a great deal of attention has been paid to the idea of low invasive treatments or minimally invasive treatments intended to minimize the burden on patients in treatments.
Under the circumstances, Interventional Radiology (to be abbreviated as IVR) has become popular, in which an operator, for example, forms a blood vessel, injects an anticancer agent, or embolizes a blood vessel as a source of nourishment for a tumor cell while operating a treatment member such as a catheter inserted into the patient""s body under X-ray fluoroscopy. X-ray diagnosis apparatuses, X-ray CT apparatuses, and the like dedicated to IVR have been developed.
Many IVR techniques are currently designed to insert catheters into blood vessels and perform various treatments. Examples of these techniques are: a technique of inserting a catheter having a balloon attached to its distal end into a blood vessel of a patient, guiding the distal end to an occluded blood vessel portion under X-ray fluoroscopy, and inflating the balloon, thereby expanding the occluded blood vessel; a technique of guiding a catheter to a bleeding region, and injecting a blood coagulant from the distal end of the catheter to occlude the bleeding blood vessel; a technique of guiding the distal end of a catheter to a region near a cancerous cell and occluding a blood vessel that feeds nourishment to the cancerous cell; and a technique of occluding a blood vessel after administering an anticancer agent from the distal end of a catheter. Recently, a technique of inserting a metal coil to an aneurysm through a catheter and occluding the aneurysm has recently been established.
Such an IVR technique allows a surgeon to perform an operation without trephination or celiotomy, and hence the burden on the patient is greatly reduced, and the patient can quickly recuperate from the operation.
An operator generally inserts a catheter from the femoral artery of a patient (object) and moves its distal end to a head portion, chest portion, abdominal portion, or the like as a treatment target region while observing an X-ray fluoroscopic image. In X-ray photographing, since the operator cannot observe a blood vessel without contrast medium administration, he/she grasps the blood vessel structure with an image photographed upon injection of a contrast medium into the blood vessel. More specifically, the operator injects the contrast medium from the distal end of the catheter into the blood vessel, and checks how the blood vessel runs while sequentially observing the contrasted blood vessel as an X-ray fluoroscopic image.
Since the injection of a contrast medium increases the physical burden on the patient (object), it is required to minimize the total amount of contrast medium. For this reason, the operator reuses a contrasted image of a blood vessel photographed upon injection of a contrast medium as a guide image, instead of sequentially injecting the contrast medium as the catheter moves, and displays this guide image and a real-time fluoroscopic image on a display unit, thereby assisting the movement of the catheter. This guide image is generally called a road map image.
In moving the catheter in practice, the operator inserts a guide wire opaque against X-rays into the catheter, and moves the guide wire first while monitoring the distal end of the guide wire with an X-ray fluoroscopic image. The operator then moves the catheter to the distal end position of the guide wire. The operator repeats this operation to move the catheter to a desired region.
As the second method, the method disclosed in Jpn. Pat. Appln. KOKAI Publication No. 1-204650 is known, in which a 2D contrasted image of a blood vessel is generated before the movement of a catheter, and the contrasted blood vessel image is used as a road map image. This road map image and a real-time image during X-ray fluoroscopy are superimposed on each other and displayed, thereby moving the catheter to a target region.
As the third method, the method disclosed in Jpn. Pat. Appln. KOKAI Publication No. 8-332191 is known, in which a target route marker is set in 3D image data of an object which includes the insertion position of a catheter and a target region to which the distal end of the catheter must traverse, and the catheter is guided to the target region along this target route maker.
In the first method, however, the 2D contrasted blood vessel image as a road map image does not always coincide in photographing direction with a fluoroscopic image during actual movement of the catheter. For this reason, it takes much time to execute this method, resulting in an increase in burden on the operator as well as the patient.
In the second method, when a blood vessel route changes relatively smoothly, the catheter can be moved very accurately along the blood vessel route. If, however, the blood vessel route changes in a complicated manner or branches off, it is not easy to move the catheter. In this case, the operator must handle the catheter with great care. Furthermore, in the third method, it is difficult to associate a blood vessel with the distal end of the catheter on a display screen, and hence the operator who operates the catheter is still required to have great knowledge and experience.
It is an object of the present invention to provide information that effectively assists moving operation of a catheter in a radiographic image diagnosis apparatus.
A radiographic image diagnosis apparatus according to the present invention includes a photographing unit having a radiation source and a 2D radiation detector to generate data of a fluoroscopic image of an object to be examined. Volume data is generated on the basis of the data of a plurality of fluoroscopic images of the object at different angles which are acquired by the photographing unit. A measuring mechanism measures the position and angle of the photographing unit with respect to the object. Projection image data is generated from the volume data on the basis of the position and angle of the photographing unit which are measured by the measuring mechanism. The volume data is then displayed. This makes it possible to display the projection image with substantially the same position and direction as those of a fluoroscopic image.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out herein after.